1. Field of the Invention
Apparatuses consistent with the present invention relate to an inductor, and more particularly, to a shredded parallel stacked inductor having a high quality factor by reducing a loss resulted from a skin effect created in metallic layers of the inductor.
2. Description of the Related Art
In general, a transceiver is a device for transmitting and receiving signals between communication appliances, and is used in diverse fields such as code division multiple access (CDMA), global system for mobile communications (GSM), wireless local area network (WLAN), ultra wideband (UWB), and other such communications fields known in the art. Such a transceiver includes constituent parts such as a voltage controlled oscillator, a low-noise amplifier (LNA), a mixer, a power amplifier, an LC filter, and other components well known in the art.
An inductor is used in the respective constituent parts of the transceiver, and a demand for an inductor having a high Q factor is recently rising. For example, the core of a design for reducing the phase noise of the voltage controlled oscillator is to employ an inductor having a high quality (Q) factor. Additionally, an inductor having a high Q factor is necessary to integrate the voltage controlled oscillator, the power amplifier, the mixer, and other known components into the transceiver.
The Q factor has a close relation with a skin effect. In order to implement the inductor having the high Q factor, a loss resulting from the skin effect created in the inductor must be reduced.
The term “skin effect” means the tendency of a high-frequency current to distribute itself within a conductor, such as metal, so that the current density near a surface of the conductor is greater than that at its core, i.e. the current tends to flow at the skin of the conductor. The reason why the skin effect occurs is that as the direction of current flowing through the conductor is abruptly changed, an induced electromotive force is produced within the conductor, and this force makes it difficult for the current to flow through the center part of the conductor. When the skin effect is created, the thickness with which the current can penetrate the conductor is called a skin thickness, which can be expressed by Equation (1),
                    δ        =                  1                                    π              ⁢                                                          ⁢              f              ⁢                                                          ⁢                              μ                O                            ⁢              σ                                                          (        1        )            
In Equation (1), δ denotes a skin thickness, f denotes a frequency, μ0 denotes permeability in a vacuum, and a denotes a conductivity of the conductor. In Equation (1), π and μ0 are fixed values, respectively.
Referring to Equation (1), as the conductivity of the conductor and the frequency of the current applied to the conductor become high, the skin thickness is decreased. Recently, an aluminum metallic layer of the inductor has been replaced with a copper metallic layer in order to implement an inductor having a high Q factor. The copper has a characteristic that the conductivity of the copper is about 56% higher than that of the aluminum. Also, the frequency of the electric current applied to the inductor is heightened as time goes on.
As the conductivity of the metallic layer and the frequency of the current applied to the inductor increase, the loss resulting from the skin effect is increased, and this loss causes the Q factor of the inductor to be reduced.